I am a contractor operating in Saudi Arabia and need to know equipment cost impact for the same capacity.

1-Screw Chillers air cooled using R134a versus R407c

2-Package Units using R 22 versus R 134a

3-Package Units using R 22 versus R 407c

4-DX Package Units using R 134a versus R 407c

Which of the options with the matching Refrigerent apply best for high Ambient temperatures + High Humidity O.A. Temp..

Same question but for high ambient + low wet bulb O.A. temp.

Which of the above will be the industry standard in the future and why.

Appreciate your professional input.

Chahine999